How Mammography is Performed: Imaging and Positioning
- Brief Overview of Mammography
- Mediolateral Oblique View (MLO)
- Cranio-Caudal View (CC)
- Medio-Lateral View (ML)
The cranio-caudal view (CC) images the breast from above. This view may be taken during routine screening mammography and during diagnostic mammography.
This illustration shows the cranio-caudal view (CC) and the mediolateral oblique view, which is taken from an oblique or angled view.
With the CC view, the entire breast parenchyma (glandular tissue) should be depicted. The fatty tissue closest to the breast muscle should appear as a dark strip on the x-ray and behind that it should be possible to make out the pectoral (chest) muscle. The nipple should be depicted in profile.
Positioning a patient for a CC view:
#1: For the CC view, the mammography technologist will lift the breast approximately two centimeters and adjust the height so that the object table touches her hand.
#2: The technologist will stand on the medial side of the breast that will be x-rayed (or behind the patient) and ask the patient to turn her head toward her. Then, the technologist will take hold of the patientâ€™s back and shoulder in order to press her closer to the table. With her other hand, the technologist will take hold under the breast from its sides and lay it on the table, drawing the breast somewhat toward her so that the lateral (outer) side is turned forward.
#3: The technologist will apply compression while making sure there are no folds on the lateral side. She will put her hand on the patientâ€™s shoulder to stretch the skin, ensuring that nothing blocks the x-ray field. When the compression is sufficient, she will ask the patient to stand absolutely still and leave to make the exposure. Click on image to view larger version.
The medio-lateral view (ML) is taken from the center of the chest outward. If no oblique projection is taken, the mediolateral position may be preferable to the latero-medial view (LM, images the breast from the outer side of the breast inward toward the center of the chest) since the lateral side of the breast, where pathological changes are most commonly found, is then closest to the film. However, if the physician wants to include as much of the medial side of the breast as possible, the LM view may be chosen.
This illustration shows the ML view, which images the breast from the medial side (the "middle") outward.
With a lateral view, the pectoral (chest) muscle should be depicted as a narrow light band on at least half of the picture. The nipple should be depicted in profile and a clear stomach fold should be visible under the breast.
Positioning a patient for an ML view:
#1: For the ML view, the mammography technologist will set the x-ray tube in a 90-degree lateral projection, ensuring that the correct slide marker is used.
#2: The technologist will set the height to the axillary (armpit) fold and ask the patient to put her arm along the object table and stretch it forward. While grasping the breast from below and drawing it out, the technologist will apply compression with one hand and place her other hand on the patientâ€™s back, pressing her toward the stand. If the other breast blocks the field, the technologist may help the patient keep it out of the way. In some cases, a wide paper plaster may be used to hold the other breast away. The technologist may attach the plaster from the patientâ€™s sternum and fix it, after drawing the breast back, onto the patientâ€™s back.
#3: When the compression is sufficient, the technologist will ask the patient to remain absolutely still. Then she will leave to make the exposure.